Resting metabolic rate and energetics of reproduction in lactating Eothenomys miletus from Hengduan mountain region

Wan-Long Zhu,Zheng-Kun Wang

doi:10.1186/s40555-014-0041-3

Abstract

It has been advocated that variation in resting metabolic rate (RMR) may affect the reproductive performance of female animals. In order to investigate the relationships between RMR and reproductive output in lactating Eothenomys miletus, body mass, RMR, food intake, litter size and mass, as well as the weight of visceral organs and gastrointestinal tract were measured in the female E. miletus prior to reproduction and at late lactation. It showed that RMR was 39.62% higher at late lactation than prior to reproduction. There was no significant correlation between RMR prior to reproduction and reproductive output. However, RMR at late lactation was positively correlated with body mass, food intake, litter size and mass, and weight of visceral organs and gastrointestinal tract at late lactation, within which RMR was more related to gastrointestinal tracts than the visceral organs. Moreover, serum leptin levels were positively correlated with body fat mass, RMR, and food intake at late lactation. Our data supported the hypothesis that animals with higher RMR during lactation may have a greater digestion and absorption capacity in the digestive system for absorbing energy and may be able to devote more energy for reproduction. Leptin may participate in the regulation of body mass in lactating E. miletus.

Highlights

It has been advocated that variation in resting metabolic rate (RMR) may affect the reproductive performance of female animals
In order to investigate the relationships between RMR, reproductive output, and visceral organs in lactating E. miletus, body mass, RMR, food intake, litter size and mass, as well as the weight of visceral organs and gastrointestinal tract were measured in the female E. miletus prior to reproduction and at late lactation
There was a positive correlation between food intake and Pri RMR and LL RMR in lactating E. miletus (Pri RMR: r = 0.677, P < 0.05; LL RMR: r = 0.780, P < 0.05, Figure 3)

Summary

Introduction

It has been advocated that variation in resting metabolic rate (RMR) may affect the reproductive performance of female animals. Sustained energy intake (SusEI) has significance in defining upper energetic limits to the ability of distribution, survival, and reproduction in mammals (Zhao 2010). Limitation of SusEI was imposed by the expenditure capacities of the energy-consuming organs, such as the mammary glands during lactation (Zhao et al 2010a). Female animals appeared to approach an upper energetic limitation of SusEI during lactation (Zhao et al 2010b). It has been reported that mammals with higher resting metabolic rate (RMR) during lactation often had lower reproductive output at interspecific levels (Thompson et al 1986).

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Discussion

Conclusion